1. Field of the Invention
The present invention relates to relays generally and, more particularly, but not by way of limitation, to a novel current sensing electromagnetic relay of simple construction.
2. Background Art
Electromagnetic relays are often used for controlling motors and processes in conjunction with a so called "holding circuit" which utilizes one set of the relay's normally open contacts. The objective of the holding circuit is to keep the relay closed after the cessation of a start pulse, for example after a start push-button has been released. The holding circuit incorporates one or several sets of normally closed contacts connected in series. One of these contacts may be operated by a stop push-button, while another may be a timer, a counter, or a limit switch, serving to stop the process at will or automatically, after a work cycle has been completed.
In addition to the functions mentioned above, holding circuits often incorporate current sensors which will stop the motor or process in case of a short circuit or overload, and such current sensors usually utilize contacts operated by separate, magnetic, or thermally operated circuit breaker mechanisms.
Accordingly, it is a principal object of the present invention to provide a current sensing relay which incorporates a holding circuit and which does not require separate thermally or magnetically operated contacts to open the holding circuit.
It is a further object of the invention to provide such a relay that is simply and economically constructed.
Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.